INCOME TAXES - Components of Income Tax Expense (Benefit) Applicable to Pretax Earnings (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Reconciliation of Provision of Income Taxes [Line Items]
Current	$ 1,330	$ 1,663	$ 1,181
Deferred	(356)	(1,060)	(730)
Income taxes	974	603	451
Aflac Japan
Reconciliation of Provision of Income Taxes [Line Items]
Current	1,196	1,275	913
Deferred	159	(160)	200
Income taxes	1,355	1,115	1,113
Aflac U.S.
Reconciliation of Provision of Income Taxes [Line Items]
Current	134	388	268
Deferred	(515)	(900)	(930)
Income taxes	$ (381)	$ (512)	$ (662)